Armor-piercing projectile



R. A. HADFIELD ET AL ARMOR PIERCING PROJECTILE Filed May 1 1923 I a/ a PatentedApr. 15, 1924.

UNITED STATES PATENT OFFICE.

ROBERT ABBOTT HADFIELD, OF WESTMINSTER. AND AUGUSTUS BASIL HOLT CLERKE,

OF SHEFFIELD, ENGLAND.

ARMOR-PIERCING PROJECTILE.

I Application filed May 1,

V T all whom it may con'cern:

.Be it known that we, ROBERT ABBOTT HADFIELD and AUcUs'rUs BASIL Hem:

CLERKE, subjects of the King of Great Brit- 6 ain and-Ireland, residing. respectively. at.

Westminster. England. and Sheffield. iu the county of York. England. have invented 'Improvements in or Relating to Armor- Pierciug Projectile, of which the following is a specification.

When a capped armor piercing projectile strikes a relatively thick hard faced armor plate, that is to say,.a thickness approaching the calibre of the projectile, obliquely at a large angle to the normal, the tendency of the projectile is to turn and set its axis at right angles to the plate during perforation thereof. As a result, whilst the projectile is passing through'the plate, its rear end portion is subjected to a heavy drag or blow by the edge portion of the hole, which, particularly when the projectile is travelling at a'comparatively low velocity, corresponding to long range firing, is liable to cause such rear end portion to be pulled or broken off. Should the break extend into the cavity within the projectile, detonation of the explosive charge therein cannot take place in an effective manner. 4

Now the present invention has for its object so to construct the rear end portion of a capped armor piercing projectile as to prevent fracture thereof owing to the cause mentioned, or, if any fracture should take place, to prevent it extending to the cavity of the pro'ectile, so that, notwithstanding 'any such the charge shall take place after the projelctile has passed completely through the ate. f

For this purpose, according to the invention, the rearorbase end'portion of an armor piercing projectile having a. pointed head, an internal cavity for explosive and a base plug, is. constructed with a deep annular groove or cavity (hereinafter called a roove) concentric with the axis of the proectile and designed to facilitate the outer portion of such base end of the projectile, constituting thev outer wall of such groove. being torn off, or giving way in the event of its being subject to a heavydrag or blow when passing through an-armor plate, without injuriously affecting the remainder of the projectile. The groove may be of wedge acture, effective detonation of I 1923. Serial No. 635,825.

or taper shape as seen in longitudinal section and extend forward from its rear open end. where it is widest, to a point in advance of the ordinary external driving band groove in the base end of the projectile where it is narrowest. In this case one of the surfaces of the groove may be of cylindrical shape and the opposite one of conical shape. Or both surfaces may be of conical shape. Or both may be of cylindrical shape. the groove being then of uniform 'cross sectional area throughout practically its whole length. The rear end of the groove is or may be closed by a cover ring screwed into the base end of the projectile. In order to prevent the said annular groove being more or less closed by inward deflection of its outer wall, under the pressure of the driving band, during firing of the projectile, it is or may be filled or fitted with a metal sleeve. for instance a steel sleeve, held in place by the cover ring referred to. The sleeve may be of the same shape in section as the groove,

so as practically to fill the groove, or it may otherwise be formed of such shape as will substantially support the outer wall of the groove and prevent. it from being pressed inward under the pressure of the driving band during firing.

In the accompanying illustrative drawings, Fig. 1 shows. in longitudinal section. part of the rear or base end portion of an armor piercing projectile constructed according to the present invention. Figs. 2 and 3 are similar views to Fig. 1 showing slight modifications.

a is the base end of the projectile formed with a deep annular groove 6 concentric with the axis of the projectile and of taper shape as seen in longitudinal section. The groove extends forward from its outer rear end, where it is widestto a point in advance of the ordinary external driving .band

groove 0 where it is narrowest. One surface of the groove may be cylindrical and the other of conical shape. In Fig. 1, the outer surface 6 of the groove is of cylindrical shape and the inner one b of conical shape, or, this arrangement may be reversed as shown in Fig. 2, or both surfaces may be cylindrical, as shown in Fig. 3. Screwed into the rear end of the projectile is a cover ring at closing the end of the groove. Into the groove 6 there may, as hereinbefore mentioned, be inserted a metal sleeve e, for the purpose stated, such sleeve being held in place by the ring d, f is the ordinary chamher in the projectile for explosive and g the ordinary base plug closing the said chamber, h being the aperture to receive a fuse.

What we claim is 1. An armor piercing projectile having an internal cavity for explosive, a base plug and a driving band groove, wherein the base end portion of the projectile is provided with a deep annular groove concentric with the axis of the projectile and extending forwardly beyond the driving band groove.

2. An armor piercing projectile having an internal cavity for explosive, a base plug and a driving band groove, wherein the base end portion of the projectile is provided with a deep annular groove concentric with the axis of the projectile and extending forwardly beyond the driving band groove, said annular groove being of decreasing cross sectional area in the forward direction.

3. An armor piercing projectile having an internal cavity for explosive, a base plug and a driving band groove, wherein thebase end portion of the projectile is provided with a deep annular groove concentric with theaxis of the projectile, the outer surface of said groove being of cylindrical shape and the inner surface of conical shape.

4. An armor piercing projectile having an internal cavity for explosive, a base plug and a driving band groove, wherein the base end portion of the projectile ismprovided with a deep annular groove concentric with the axis of the projectile and extending forwardly beyond the transverse plane of the forward portion of the driving band groove, and means closing the rear end of Silld annular groove.

5. An armor piercing projectile having an internal cavity for explosive, a base plug and a driving band groove, wherein the base end portion of the projectile is provided with a deep annular groove concentric with the axis of the projectile and extending forwardly to underlie the driving band groove, and a supporting sleeve located within said annular groove.

6. An armor piercing projectile having an internal cavity for explosive, a base plug and a. driving band groove, wherein the base end portion of the projectile is provided with a deep annular groove concentric with the'axis of the projectile and extending forwardly beyond the transverse plane of the forward portion of the driving band groove, a supporting sleeve located within said groove, and means for normally holding said sleeve in position.

7. An armor piercing projectile having an internal cavity for explosive, a base plug and a driving band groove, wherein the base end portion of the projectile is provided with a deep annular groove concentric with the axis of the projectile and extending forwardly beyond the driving band groove, and of gradually decreasing cross sectional area in the forward direction and a ring screwed into the base end of said projectile and closing the rear end of the annular groove therein.

8. An armor piercing projectile having an internal cavity for explosive, a base plug and a driving band groove, wherein the base end portion of the projectile is provided with a deep annular groove concentric with the axis of the projectile, extending for- \vardly beyond the driving band groove and nearer to the exterior of said base end of the projectile than to the base plug, a metal sleeve fitting said annular groove and a ring screwed into the base end of the projectile and closing the rear end of said annular groove.

9. -An armor piercing projectile having an internal cavity for explosive, a base plug and a driving band groove, wherein the base end portion of the projecti e is provided with a deep annular groove concentric with the axis of the projectile'and extending forwardly beyond the transverse plane of the forward portion of the driving band groove, said groove providing an outer annular and weakened base end portion having the driving band groove formed therein, a supporting sleeve located within said groove and means for securing said sleeve in position and closing the rear end of said an nular groove comprising 'a ring member having threaded engagement with the outer annular and weakened base end portion.

Signed at "London, England, this seventeenth day of April, 1923.

' ROBERT ABBOTT HADFlEl-D.

AUGUSTUS BASIL HQL'PCLERKE. 

